Electrically heated pad



Feb. 26, 1957 H. B. WOLF ELECTRICALLY HEATED PAD Filed. Dec. 14, 1953 7F /z// A I I g T1 g-Z INVENTOR Z ATTORNEYJ.

United States Patent ELECTRICALLY HEATED PAD Herman B. Wolf, Charlotte,N. C. Application December 14, 1953, Serial No. 397,906 9 Claims. (Cl.219-46) This invention generally relates to floor coverings and, moreespecially, to an improved rug or carpet warming or heating mat or padfor disposition beneath a rug, carpet or the like for transmitting heatthereto.

Heret-ofore, various attempts have been made to develop a pad suitablefor underlining floor coverings, such as rugs, carpets and the like inwhich means were incorporated for effectively concealing from both sightand feel the fact that electrical conductors, heating elements or thelike were disposed between the folds or plies of the pad. However, inorder to effectively conceal the electrical conductors and resistancewires, it has been necessary to sacrifice resiliency in the pad and,more especially, a substantial proportion of the heat radiated by theconductors or heating elements has been conducted away from the uppersurface of the floor covering by the floor upon which the pad waspositioned and the resultant dissipation of heat has required relativelylarge heating elements for a pad of a given size in addition to arelatively extensive period of time being required to effectively heatthe pad or the rug, carpet or the like positioned thereon. Moreover, nomedium of high heat conductivity has heretofore been provided forconducting heat from the heating elements and diffusing it throughoutthe mat.

It is therefore the primary object of this invention to provide animproved mat or pad having an electrical resistance means or heatingelement therein and having means for effectively concealing from bothsight and fee] the presence of the electrical resistance means andproviding a means of diffusing or conducting heat throughout the mat,without sacrificing resiliency of the pad, and, also, wherein a heatreflective member, such as aluminum foil or the like forms one of theplies of said mat or pad and is disposed adjacent the opposite side ofthe electrical resistance means from that which supports the carpet, rugor the like to thereby reflect the heat and cause the same to beradiated upwardly in the direction of the rug or carpet supported on themat or pad.

It is another object of this invention to provide an improved electricheating pad or mat and method of making same, which pad comprises a pairof spaced resilient plies formed from rubber, plastic or other resilientweb material between which an electrical conductive means is positionedand formed with spaced parallel runs which .extend throughout the widthof the pad or mat and wherein a layer or ply of shredded metal, such assteel wool, is positioned on each side of the heating element orelectrical conductive means and between each of the runs thereof. Thesteel wool is then coated or impregnated with a suitable adhesive binderwhich is permitted to dry while the steel wool is under compression. Thebinder adds to the resiliency of the steel wool plies and preventscorrosion or rusting of the steel wool.

The outer surface of one of said resilient plies is covered with a thinply of metallic material, such as aluminum or tin foil with the brightor polished side Ihereof facing the corresponding resilient ply. Aloosely woven fabric, such as burlap, is positioned against the outersurface of the ply of heat reflecting material. Thus, the resiliency ofthe pad is maintained, and heat from the resistance elements is diffusedthroughout the mat due to the novel arrangement of the shredded metal orsteel wool between the proximal surfaces of the resilient plies whileeffectively concealing the heating element from both sight and feel.Also, the heat reflecting surface, embodied in the sheet or layer ofmetal foil, causes the heat radiated by the heating element to bereflected upwardly therefrom and toward the resilient ply upon which therug or carpet is positioned.

It is also contemplated that the improved heating pad construction may,in itself, constitute a suitable floor covering and serve as the visiblecovering member.

Some of the objects of the invention having been stated, other objectswill appear as the description proceeds, when taken in connection withthe accompanying drawings, in which- Figure l is a plan view of theimproved electrically heated pad or mat showing opposite corners of theuppermost ply thereof rolled upon itself with others of the plies andportions of the coils of the heating element being broken away forpurposes of clarity;

Figure 2 is an enlarged fragmentary vertical sectional view through theimproved pad or mat taken along line 2-2 in Figure 1;

Figure 3 is a view, on a reduced scale, similar to Figure 2, but beingtaken along line 3-3 in Figure l.

Referring more specifically to the drawings, the improved irug pad ormat is broadly designated at 10 and comprises a first outer or bottomsheet or ply 11 made up of a suitable fabric, preferably an open weavefabric such as burlap. Positioned upon the fabric ply 11 is a layer orply 12 of impervious heat-reflecting material, such as metal and whichis preferably in the form of metallic foil such as tin foil or aluminumfoil. As is well known, foil is generally of substantially the samethickness as writing paper and the thickness thereof is proportionatelyexaggerated in Figure 2 for purposes of clarity.

As is generally known, one surface of foil is usually relatively brightand the opposite surface thereof is usually relatively dull and, suchbeing the case, the dull surface of the foil layer 12 should bepositioned against the inner or upper surface of the fabric ply 11 andthe dull surface of the foil ply 12 is preferably adhesively secured tothe inner surface of the fabric ply 11. Thus, the bright upper surfaceof the foil ply 12 serves as a heat reflecting surface.

Adhesively or otherwise secured to the upper surface of the foil ply 12is a relatively thick layer, ply or sheet of resilient or rug mattingmaterial 13 which is preferably made up of rubber or felt or fiberswhich are suitably matted together to become intermingled and cohesivelyheld together to form a thick resilient fabric or mat layer.

Positioned upon the upper end and side outer edge portions of therelatively thick layer 13 of resilient mate rial in Figure l, andpreferably being adhesively secured thereto, is a resilient border stripor filler strip 14 which is made from any suitable resilient material,such as rubber or its equivalent. The lower edge portion of the ply orlayer 13 has a composite border strip or filler strip adhesively securedthereto which includes two parallel spaced sections 14a (Figure 3) toaccommodate lead wires or conductors therebetween, to be laterdescribed. The border strips 14, 14a define the side Walls of a heatingelement chamber within which a suitably insulated coiled heatingelement, resistance conductor or other electrical conductive means 15 isdisposed, the coils of the heating element 15 being arranged in closelyspaced generally parallel relationship.

As illustrated in Figures 1 and 2, the coils of the heating element'rest upon a layer or ply 17 of fibrous or shredded metal, such as steelwool, which, in turn, rests upon the upper surface of the relativelythick resilient ply 13. The shreds or fibers in the layer17extend ingenerally parallel relationship transversely of the runs or coils of theheating element or resistance conductor 15.

After the coils of the heating element 15 have been positioned upon theresilient shredded metal layer or ply 17, another ply 20 of materialidentical to the material in the ply 17 is formed between adjacent runsor coils of the heating element 15, but wherein the fibers or shredsextend in substanitally parallel relationship and substantially parallelto the adjacent runs or coils of the heating element or the resistanceconductor 15. Positioned upon the ply 20 and the coils of the heatingelement or resistance conductor 15 is a resilient shredded metal orsteel wool ply 21 which is similar to the ply 17 and wherein the fibersor shreds thereof are also arranged in substantially parallelrelationship transversely of the coils or runs of the heating element orresistance conductor 15. The three matted layers of fibrous or shreddedmetal 17 20 and 21 actually become intermingled to some extent when theimproved rug pad or mat is assembled and the three layers 17, 20 and 21are collectively of substantially the same thickness as the border orfiller strip 14 thus serving, with the coils of the heating element 15,as a filler between the resilient cover or ply 13 and a second outer orupper resilient ply or cover 26. In order to prevent shifting of theshredded or fibrous metal in the layers 17, 20 and 21, each of theselayers is preferably coated or impregnated with a suitable adhesivehinder or compound such as varnish, plastic, rubber or other material.This binder also prevents rusting or corrosion of the steel wool orfibrous metal and adds to its resiliency.

When the fibrous or shredded metal layers 17, 20 and 21 are initiallypositioned about the coils of the heating element 15, it is apparentthat the fibers or shreds thereof are relatively loose and, in order toinsure that an ample amount of said fibers is provided between theresilient plies 13 and 26, the fibrous metal layers 17, 20 and 21 aresuitably compressed after the binder has been applied thereto and whilethe binder is still in the wet state. The fibers remain compressed untilthe binder has dried. Thus, after the binder has dried or hardenedsufiiciently, the shape of the mat formed from the shredded metal plies17, 20 and 21 is retained so the upper surface of the upper resilientply 26 is smooth and flat throughout. Other arrangements of the heatconducting shredded metal may be made.

Suitably insulated lead wires 22 and 23 are connected to opposite endsof the heating element, resistance conductor or other electricalresistance means 15, adjacent opposite ends of the filler strip sections14a. The lead wires 22 and 23 penetrate the innermost filler stripsection 14a, extend longitudinally between the filler strip sections andthen penetrate the central portion of the outermost filler strip section14a. A suitable plug 24 is connected to the free ends of the wires 22and 23 and is adapted to be connected to a suitable source of electricalenergy.

The second outer or upper resilient ply, cover or layer 26 is positionedupon and adhesively secured to the upper surface of the upper layer 21of shredded or fibrous metal with its outer edge portions being suitablyadhesively secured to the upper surface of the filler strip or borderstrip 14 and the sections 14a. The upper ply 26 is preferably made frommolded rubber or plastic, felt, or textile fibers which are suitablymatted together to become intermingled and cohesively held together. Theupper ply or layer 26 is preferably, but not necessarily, of slightlyless thickness than the layer 13, the proximal surfaces of the layers orplies 13 and 26 defining the lower and upper walls, respectively, of theheating element chamber or resistance conductor chamber.

In order to insure that the adhesive used in securing the opposing plies13 and 26 to the steel wool plies 17 and 21 and the border strip 14 isdried completely and to thereby insure that the improved rug pad is freeof undesirable odors caused by the adhesive, it is highly desirable thatone corner of the upper resilient ply 26 is turned upon itself,substantially as shown in the righthand lower portion of Figure l, for asufficient period of time to permit the moisture in the adhesive toevaporate and to thereby release the odor of the adhesive from theheating element chamber. Thereafter, the previously turned corner of theupper ply 26 is adhesively secured to the previously exposed cornerportions of the steel wool ply 21 and the border or filler strip 14.

It is apparent that the combination of the steel wool or fibrous metallayers 17, 20 and 21 and the resilient layers 13 and 26 disposed onopposite sides of the fibrous metal or steel wool layers effectivelyconceals the coils of the electrical resistance means or heating element15 from both sight and feel and provides an efiective means forconducting heat from the resistance elements, and diffusing this heatthroughout the mat without sacrificing resiliency of the pad 10,although the heating element traverses the same general area .as thatdefined by the rug mat or pad 10. In addition, of great import is thefact that heat radiated by the coils of the heating element orelectrical resistance means 15 is reflected upwardly away from the floorF by the foil ply 12, thus preventing undue heat loss and insuring thatthe air surrounding and immediately above the rug pad 10 is efficientlyheated and, of course, insuring that the rug, carpet or the likepositioned upon the upper surface of the layer 26 of the improved rugpad 10 is heated with a minimum amount of current being consumed by theheating element 15. The steel wool or metal fibers in the layers 17, 20and 21 also assist materially in uniformly diffusing the heat radiatedby the coils of the heating element 15. Also, the resilient opposedcovers or plies 13 and 26 and the border or filler strips 14, 14a arepreferably made from a waterproof material to prevent dust, moisture andthe like from entering the chamber in which the heating element 15 andthe steel wool plies 17, 20 and 21 are disposed.

' It is thus seen that I have provided a novel floor covering, apreferable form of which may be in the nature of a rug pad or mat fordisposition beneath a decorative floor covering and which is arranged toelfecti'vely accommodate and conceal both from sight and feel,electrical resistance means or heating element coils, and means fordiffusing heat uniformly throughout the rug or mat without sacrificingthe resiliency of the rug pad and, further, being so arranged as toeffectively radiate the heat up- Wardly or away from the floor so that apredominant amount of the heat is not dissipated to or conducted by thefloor.

In the drawings and specification there has been set forth a preferredembodiment of the invention and, although specific terms are employed,they are used in a generic and descriptive sense only and not forpurposes of limitation, the scope of the invention being defined in theclaims.

I claim:

1. A heat radiating pad comprising a pair of opposing covers, a coiledheating element having spaced coils arranged between said opposingcovers, a fibrous metal pad construction disposed between said opposingcovers and in which said coils of the heating element are embedded, anda foil sheet on the exterior surface of one of said opposing covers.

2. A resilient rug pad comprising upper and lower spaced resilient pliesof non-metallic material, a fibrous metal mat construction disposedbetween said spaced resilient plies, a heating coil embedded in the matof fibrous metal, .and a sheet of metal foil applied to the exteriorsurface of one of said resilient plies.

3. An improved floor covering construction comprising a pair of spacedopposing resilient plies, a compressed steel wool mat disposed betweensaid opposing plies, said steel wool mat being impregnated with anadhesive binder, a heating element having coils arranged between saidpair of opposed plies and being embedded in said steel wool mat, and asheet having a heat reflecting surface thereon adhesively secured to theouter surface of one of said opposing resilient plies.

4. An improved floor covering construction comprising a pair of spacedopposing resilient plies, a relatively narrow filler strip disposedbetween adjacent edge portions of said pair of opposing resilient plies,a compressed steel wool mat disposed. between said opposing plies andbeing confined therebetween by said filler strip, said steel wool matbeing coated, at least in part, with a liquid binder of a characterwhich becomes solidified after application thereof, a heating elementhaving coils arranged between said pair of opposing plies and beingembedded in said steel wool mat, and an impervious sheet having a heatreflecting surface thereon adhesively secured to the outer surface ofone of said opposing resilient plies.

5. An improved floor covering construction comprising a pair of spacedopposing waterproof resilient plies, a relatively narrow filler stripdisposed between adjacent edge portions of said pair of opposingresilient plies, a compressed fibrous metal mat disposed between saidopposing plies and being confined therebetween by said filler strip,said fibrous metal mat being impregnated with a liquid binder of acharacter which becomes solidified after application thereof, a heatingelement having coils arranged between said pair of opposing plies andbeing embedded in said fibrous metal mat, and an impervious sheet havinga heat reflecting surface thereon adhesively secured to the outersurface of one of said opposing resilient plies.

6. An improved rug pad construction comprising a pair of opposingresilient plies, a layer of fibrous metal disposed between and engagingthe proximal surfaces of the opposing resilient plies, a heating elementhaving a plurality of closely spaced substantially parallel coilsembedded in said layer of fibrous metal, said layer of fibrous metalbeing impregnated with an adhesive binder, a foil sheet secured to theexterior surface of one of [said opposing resilient plies, and a burlapfabric ply secured to the exterior surface of said foil sheet.

7. An improved rug pad construction comprising a pair of opposingresilient waterproof plies, a border strip of waterproof materialdisposed between and being adhesively secured to edge portions of saidresilient plies, first and second spaced plies of fibrous metal disposedbetween and engaging the proximal surfaces of the respective opposingresilient plies and having their fibers extending in substantiallyparallel relationship, a heating element having a plurality of closelyspaced substantially parallel coils disposed between said first andsecond plies of fibrous metal and wherein said coils extend transverselyof the fibers in said first and second fibrous metal plies, a thirdfibrous metal ply disposed between the proximal surfaces of the firstand second fibrous metal plies and being disposed between adjacent coilsof said heating element, the

fibers in said third fibrous metal ply extending in substantiallyparallel relationship and substantially parallel to the adjacent coilsof the heating element, and an adhesive binder coating on said fibrousmetal plies.

8. An improved rug pad construction comprising a pair of opposingresilient waterproof plies, a border strip of waterproof materialdisposed between and being adhesively secured to edge portions of saidresilient plies, first and second spaced plies of fibrous metal disposedbetween and engaging the proximal surfaces of the respective opposingresilient plies and having their fibers extending in substantiallyparallel relationship, a heating element having a plurality of closelyspaced substantially parallel coils disposed between said first andsecond plies of fibrous metal and wherein said coils extend transverselyof the fibers in said first and second fibrous metal plies, a thirdfibrous metal ply disposed between the proximal surfaces of the firstand second fibrous metal plies and being disposed between adjacent coilsof said heating element, the fibers in said third fibrous metal plyextending in substantially parallel relationship and substantiallyparallel to the adjacent coils of the heating element, an adhesivebinder coating on said fibrous metal plies, a foil sheet adhesivelysecured to the exterior surface of one of said opposing resilient plies,and a loosely woven fabric ply adhesively secured to the exteriorsurface of said foil sheet,

9. An improved rug pad construction comprising a pair of opposingresilient plies, first and second spaced plies of fibrous metal disposedbetween and engaging the proximal surfaces of the respective opposingresilient plies and having their fibers extending in substantiallyparallel relationship, a heating element having a plurality of closelyspaced substantially parallel coils disposed between said first andsecond plies of fibrous metal and wherein said coils extend transverselyof the fibers in said first and second fibrous metal plies, a thirdfibrous metal ply disposed between the proximal surfaces of the firstand second fibrous met-a1 plies and being disposed between adjacentcoils of said heating element, the fibers in said third fibrous metalply extending in substantially parallel relationship and substantiallyparallel to the adjacent coils of the heating element, a foil sheetadhesively secured to the exterior surface of one of said opposingplies, and a loosely woven fabric ply adhesively secured to the exteriorsurface of said foil sheet.

References Cited in the file of this patent UNITED STATES PATENTS1,120,259 Wiegand Dec. 8, 1914 1,172,025 Homan Feb. 15, 1916 2,215,042Howard et al. Sept. 17, 1940 2,246,795 Daniels June 24, 1941 2,247,623Von Hofe July 1, 1941 2,371,288 Frownfelter Mar. 13, 1945 2,390,863Amidon et al. Dec. 11, 1945 2,415,187 Moore Feb. 4, 1947 2,511,540Osterheld June 13, 1950 2,533,409 Tice Dec. 12, 1950 2,619,580 PontiereNov. 25, 1952

